Method of and apparatus for operating steam-boiler economizers



V D. s. moosus, METHOD OF AND APPARATUS FOR OPERATING-STEAM BOILER ECONOMIZERS.

APPLICATION FILED NOV. 4, I919.

Patented May 16, 1922.,

a c n e v a s n e u a z o o a uwa c b n a o e caucus WW S w W m/ w citizen of the United States, residing at Jersey Cigy, in the county of Hudson and UM En'sT TIas I Parent canine;

DAVID S. JACOBUS, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE BABCOGK & WILCOX COMIANY, OF BAYONNE, N EW JERSEY, A CORPORATION OF NEW JERSEY.

l lLlETHOD OF AND APPARATUS FOR OPERATING STEAM-BOILER ECONO'MIZEBS.

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Specification of Letters Patent. ll atenibqgill May 16, 1922.,

Original application filed December 8,1914, Serial No. 876,012'. Divided and this application filed November 4, i919. Serial No. 335,727.

To all iohom z'tmay concern:

Be it knownthat I, DAVID S. JAooBUs, a

State of i ew Jersey, have invented. certain new and useful Improvements. in Methods of and Apparatus for Operating Steam- Boiler Economizers, of whichthe following is a specification. X

The present invention relates to economizer practice and is designed to increase the efficiency of economizers' and steam boilers, as well as the efliciency of the entire boiler and economizer system. In this connection, the invention is also designed to remove dust, acid fumes and other solids from the waste gases. To that end, the invention consists in introducing moisture into the waste gases of the boiler after they have passed one part orsection of an economizer, and then' passing the moistened and cooled gases over another part or section of the economizer an-d condensing thereon a portion of the introduced moisture.

This invention differs essentially from the introduction of moisture between a boiler and an econo'mizer, in the following features.

(1) The lIltI'OdllCtlOILOf the moisture between sections of an economizer has a much less deleterious effect on the draft reslstance of the gases flowing through the boiler to the stack then where moisture is introduced bfl tween the boiler and the economizer as a whole. by the economize'i' is greater than it would be if the moisture were introduced between the boiler and the-economizer. (3) Acid fumes may be condensed and removed between the economizer sections, and before the cooled gases reach those parts of the economizer where the moisturewould condense.

My invention will best be understood by reference to the accompanying drawing,

which is a diagrammatic side elevation, par- I tially in section, of a steam boiler embody ing my invention. Referring to thedraW- mg, the numeral 1 designates a boiler of standard design, having a transverse steam and water drum 44, and fired with a .chain grate stoker 3, the waste gases from the (2) The amount of heat absorbed boiler escaping through a flue'in which the economizer and spraying devices are located. For the purpose of describing one method of practicing the invention, I have shown a two .-stage' economizer with means for eliminating the air from the water before it is delivered to the high pressure stage. The

latter'isdesignated generally by the letter A and is shown as located in a vertical flue 4t, and as subjected'tothe hottest gases. The gases are made to flow in a downward direction over the tubes of the high pressure stage, and the fiow of water through said stage/is, in general, in the reverse direc tion of the flow of the gases. pressure stage of the economizer COIlSlStS, of a series of rows of tubes 6' expanded into direction of the flow of the water. The tubes and boxes are preferably of wrought iron-or wrought steel, to withstand the high boiler mizer is subjected.

- In the drawing illustrating the invention covered by my present application, a. part tubes expanded into horizontal headers or The high a horizontal boxes or headers 7,said tubes havin a slight inclination upward in the pressure to which this stage of the econoboxes, and is similar .in construction to" the high pressure stage A. ,The tubes and boxes of section C,if of wrought iron or wrought steel, are preferably coated both inside and outside with a protective coating, to prevent corrosion. The section C. of the low pressure stage is shown as consisting of two separated banks 37 and 38 of vertical tubes connected to upper horizontal boxes 39 placed at different levels, and lower horizontal boxes 40,

also placed at diflerent levels. In this arrang'ement, the feed water. enters pipe ll and is distributed through the lower boxes 40, and thence flows up vard through all of the tubes 37 and 88, and escapes from the upper boxes 39, through pipe 42, to the lower part of section C of the low pressure stage.

' The water leaves the upper part of said stage through a" pipe and is delivered to tank 17, from which it is fed to the lower part of the high pressure stage A. by the pump 20. "FIOII1 the high pressure stage the water is' forced'into'the drum 44 ,of the boiler.. In tank 17 are, preferably, perforated plates overwhich the water is-rnade to flow, and by whim it is broken up, to facilitate'the disengagement and escape of air and gases from the water, such disengagement being assisted by heating the waterin thelow pressure stage of the economizer, and, if desired; by maintaining a partial vacuum in the tank by any suitable means, such as the dry vacuum pump 50; or the air and gases are permitted to escape through a relief valve 18.

From the tank 17 the water is conducted by a pipe 19 to a feed. pump 20, which forces it through a pipe 21 to the lowerpart of the high pressure stage of the economi' zer. "The water enters the lowermost header 7 and flows from side to side through successive rows of tubes, and is delivered from the'high pressurestage, through pipe 22, intothe steam and water-drum 44. This flow'of the'water through the high pressure stage of the econ omizer provides fora positive circulation and the passage through-tubes all of. which are inclined upward with reference to the direction of flow of the water, and, in general, in

M the reverse direction of the flow ofthe gases.

It is well known that the rate of heat transfer from steam or liquidsto a cooler surface, such as a tube wall, is-much higher than the rate of transfer from gases at the same temperature to the same cooler surfaee, and this principle is utilized by me in the operationof a steam boiler economizer. In the arrangement shown, I introduce water, or steam, or

both, into the gases between the high and low pressure stages of theeconomizer, one means for such purpose being a seriesof perforated pipes 23 ,connected to boxes located in the flue 4 below. the high pressure stage Alof the economizer. As shown, the wall 4 of the. flue 4 stopsshort of the bottom of the flue, so that the gases will flow through thep'as sage below the wall; 4 and upward to the opening into the fine in which the section C of the low pressure section of the economizer is disposed. The water or steam is delivered I to the pipe 23 by any suitable means. The

' escapes in fine streams or spray. Any suit water-may be supplied to the well 26 at the bottom of the flue 4 by a pipe 27, and pumped from the well by a pump 28, through pipe.

29, to the perforatedv pipes 23, from which it able means other than'perforated pipes may be used for spraying the water.

In this arrangement, the water spray is, introduced through the pipes 23fbetween the high pressure stage A and the section 0 of the low pressure stage.

That part of the water which is not evaporated after spraypressure stage .of the economizer.

ing through the gases and after passing over the section 0, collects in the well 26 in the lower part of flue 4, from'which it is raised by the pump 28, through pipe 29, into the sprayer 23, and may" thus be used over and over again, if desired. The gases, after passlng over the section C, flow over the sectlon C of the low pressure stage, where the steam I and water vapor is condensed, and flow down the inclined floor 45 into-a well 46. The latter is connected by pipe/47 with the well 26 to equalize the water levels. The gases finally enter the induced draft fan 34 and from thence are delivered to the stack 35.. The

spraying of the economizer removes therefrom any condensation products from the gases whlch would cause corrosion, and 1n case any acid is present, it is diluted and rendered harmless for ordinary conditions of operaflue 4, through which access'may be had to Doors 26 may be provided in the wall of the well 26 for the purpose of washing out i the sediment through pipe 33, or the sediment may be shoveled out through the doors.

. When the water is sprayed into the gases, as above. described, the water will be partly evaporated and will reduce the temperature of the gases, as a. limit, to approximately 212 F., andthis will produce a considerable volume of steam, which will be condensed as the gases pass over the last section of the low This cooler stage of the economizer will be -more activein absorbing the heat from the steam and moist gases than the same section would be in absorbing heat from relatively, dry

gases.

As above stated, steam alone, or steamandwater, may be used for moistening and wash- 1ng the gases. In plants where the mam steam motors are run non-condensing andin some plants where the main steam motors are run condensing, and where there are noncondensing auxiliary units, there is a surplus of exhaust steam, and this exhaust steam could be used in place of water.

Steam would give additional heat to the economizer and would serve to throw down the Cinders. i In addition-to the advantage of an in creased rate of heat transfer due to the addition of moisture to the gases, there is a further advantage, in that the means de scribed provide for the removal of soot, cinders and tar from the gases. In certain plants there is much trouble with the deposition of tar from the furnace gases on the coolest tubes of the economizer. This tar carries with it soot from the gases, the whole forming a pasty mass which cannot be effectively scraped from the tubes, and which collects at the lower ends of the tubes and above the lowermost headers. By using a water spray or steam, in the manner described, the greater part of the tar and soot will be carried down and deposited in the well 26. In the arrangement covered by my present application, there is a substantially greater increase in efficiency than in the arrangement shown in Fig. 1 of my prior application, due to the greater heat; absorption, by reason of the wetting of the surfaces of the tubes of section C of the low pressure stage of the economizer and the condensa- 5 .tion.

tion of moisture in the section C. Furthermore, as stated, the spraying of the economizer protects the same from corrosion by removing from the surface thereof any products condensed from the gases which would tend to produce corrosion.

As has been stated, the drawings are diagrammatic. Certain common and well known features, such as safety or relief valves for the economizers, have not been shown, in order to emphasize the features which apply more particularly to the inven- Regulating the supply of makeup water and maintaining the proper levels of water in the hot wells, as well as regulating the water levels in the mixing tanks or heaters. may be carried out in many well known ways. These are operating features aside from the principles of my invention which I have described.

\Vhile I have herein shown and described one modification of my invention, I do not desire to be limited to the exact arrangement shown and described, but seek to cover, in'the appended claims, all those modifications which come within the true spirit and scope of my invention.

' lVhat I'claim and desire to secure by Letters Patent of the United States is:

1. The herein-described method of operating a steam boiler, consisting in passing the gases over one partof an economizer, then passing themover another part of the economizer, and sprayingwater over the latter part of the economizer as the gases-pass thereover.

2. The method of operating a two-stage economizer which consists in passing the gases over the two stages in succession and.

of the economizer and spraying the gases while passing thereover, and then passing the gases over a further cooler and unsprayed part of the economizer.

4. The method of operating a steam boiler comprising an economizer having high and low pressure stages, and the low pressure stage of which comprises two sections, which consists in passlng the gases over the high pressure stage, then passing them over the first section ofthe low pressure stage and spraying the gases while passing thereover, and then passing the sprayed gases over the second section of the low pressure stage.

5. The method of operating a-steam boiler having an outlet flue in which an economizer is set which consists in adding to a liquid a corrosion-preventing chemical reagent and spraying the reagent-containing liquid over the cooler portion of the economizer to wash of? any corrosive materials and thereby prevent corrosion.

6. A steam boiler planthaving a waste flue and an economizer in said waste fiue divided into separated parts, and means for spraying water into the gases over one of said parts.

7. A steam boiler having a waste flue for the products of combustion, an economizer in said waste flue divided into separated parts, means for spraying water into the gases over one or said parts, and another part of the economizer over which the moist gases thereafter flow.

8. A steam boiler plant having a waste flue comprising a vertical portion, an economizer disposed within said flue and divided into two stages, one stage of which comprises two sections, one stage and only one of the sections of the other stage being disposed within the vertical portion of said fine, and means for spraying the gases while passing over said section in said fine.

9. A steam boiler plant having a waste flue comprising a verticalportion, an economizer comprising high and low pressure stages, the low pressure stage comprising two sections, the high pressure stage and' only one section of the low pressure stage being disposed within the vertical portion of said flue, and means for spraying the gases during their passage over said low pressure section.

DAVID s JACOBUS. 

